JP4820653B2 - Covering member - Google Patents

Description

  The present invention relates to a covering member that is particularly excellent in weather resistance in resin members used for various interior materials and organic glass.

  Resin materials are widely used in various applications by making use of characteristics such as impact resistance and light weight. Among them, transparent resin materials represented by polycarbonate, etc. have special features such as low specific gravity, easy processing, and resistance to impact compared to inorganic glass. It is used for various applications and in optical fields such as lenses and optical fibers. On the other hand, the resin material is easily damaged by the surface, easily loses its gloss and transparency, is easily attacked by organic solvents, has poor weather resistance (for example, light stability against ultraviolet rays and infrared rays), heat resistance, etc. Has drawbacks. Therefore, resin materials are used by being coated with various coatings in order to improve the surface characteristics. In particular, when a resin material is used for an automobile window glass or an interior material, it is often exposed to sunlight for a long period of time. Therefore, it is necessary to suppress photodegradation of a base material made of a resin material by forming a film. is there.

  For example, Patent Document 1 discloses a primer layer having an ultraviolet absorbing ability in which an ultraviolet absorbing group is immobilized on a polymer main chain by a chemical bond. The primer layer of Patent Document 1 can impart an ultraviolet absorbing ability without deteriorating the adhesion to the base material because the ultraviolet absorber group is immobilized on the polymer main chain by a chemical bond. Patent Document 2 discloses a hard coat layer made of a composition containing a reaction product of an organosilicon compound and a metal alkoxide containing a β-diketone group. Since the composition of Patent Document 2 has almost no uncrosslinked portion even under mild curing conditions, the occurrence of cracks due to cross-linking over time is reduced.

In Patent Document 1, in order to further improve the ultraviolet absorbing ability, it is necessary to increase the amount of the component having the ultraviolet absorbing ability by increasing the thickness of the primer layer. However, when the thickness of the coating is increased, problems such as cracks in the coating tend to occur. Further, even when a hard coat layer made of a composition as disclosed in Patent Document 2 is used, when a primer layer is used between the base material and the hard coat layer, the linear expansion coefficient of the primer layer is the hard coat layer. Therefore, the increase or decrease of stress occurs in the hard coat layer due to expansion / contraction of the primer layer due to temperature change or the like, and cracks are likely to occur in the coating.
JP 2001-214122 A JP 2001-348528 A

  The inventor of the present application pays attention to the above problems and aims to provide a covering member having a coating having excellent adhesion and crack resistance.

The covering member of the present invention has a resin base material, a primer layer formed on the surface of the resin base material, and a hard coat layer formed on the primer layer,
The primer layer includes a thermosetting acrylic resin and a thermoplastic acrylic resin, and an acrylic primer (provided that the weight ratio of the thermosetting acrylic resin to the thermoplastic acrylic resin is 95: 5 to 30:70) , Except for acrylic primers including PC-7A manufactured by Shin-Etsu Chemical Co., Ltd. and PUVA-30M manufactured by Otsuka Chemical Co., Ltd.)
The hard coat layer contains 3 to 60 wt% of a flexibility imparting agent when the hard coat layer is 100 wt% ,
Before SL primer layer and / or the hard coat layer is characterized by containing the ultraviolet absorbent.

  Here, an ultraviolet absorber refers to what has the capability to absorb the light whose wavelength is mainly 400 nm or less, more specifically 200 to 400 nm. The ultraviolet absorber may be a general organic ultraviolet absorber or an inorganic ultraviolet absorber, or, for example, an immobilized ultraviolet absorber fixed to a resin primer by a chemical bond.

  In the covering member of the present invention, it is preferable that the hard coat layer contains 3 to 60 wt% of the flexibility imparting agent when the hard coat layer is 100 wt%. Moreover, it is preferable that the said primer layer contains a ultraviolet absorber and the film thickness is 8 micrometers or more.

  In the covering member of the present invention, the hard coat layer contains a flexibility imparting agent, thereby increasing the critical elongation at break of the hard coat layer. As a result, the coated member has a coating film excellent in crack resistance (weather resistance) and adhesion (weather resistance). Under the present circumstances, it is preferable that a hard-coat layer contains 3-60 wt% of flexibility imparting agents, and can improve the crack resistance and adhesiveness of a film further more favorably.

  Further, in the covering member of the present invention, when the primer layer and / or the hard coat layer contains an ultraviolet absorber, the amount of ultraviolet rays reaching the resin base material can be reduced. Can be reduced. As a result, the weather resistance adhesion at the interface between the substrate and the coating is improved. At this time, if the primer layer is 8 μm or thicker and the film is thick, the upper limit of the ultraviolet absorber that can be added to the primer layer increases, so that the photodegradation of the resin substrate can be further reduced. As a result, the weather resistance adhesion is further improved.

  Below, the best form for implementing the coating | coated member of this invention is demonstrated using figures.

The conventional covering member consisting of a resin base material, primer layer, and hard coat layer is not only affected by the hardness of each part and the influence of the interface, but also due to changes over time due to light, etc. Produce. For example, as shown in FIG. 4, for example, the primer layer 2 and the hard coat layer 3 formed on the surface of the resin substrate 1 usually have a large difference in linear expansion coefficient α (for example, an acrylic primer layer). ^Therefore , α = 3 × 10 ⁻⁴ and α = 8 × 10 ^{−5 in} the case of a silicon-based hard coat layer), so that the primer layer expands and contracts (eg, arrow 6) due to the temperature change over time. (FIG. 4 (I)). Therefore, the hard coat layer is repeatedly stressed by the expansion and contraction of the primer layer, so that cracks 7 occur in the coatings (2, 3) (FIG. 4 (II)). Furthermore, the crack 7 is likely to be generated by the progress of cross-linking over time due to heat or light and the elongation of the hard coat layer is reduced. Further, as shown in FIG. 5, even if the primer layer 2 and the hard coat layer 3 include the ultraviolet absorbers 20 and 30, the general ultraviolet absorber disappears with time due to light and water. As a result, the surface 8 of the resin substrate 1 is deteriorated by ultraviolet rays (FIG. 5 (I) → (II)). Then, water enters the deteriorated surface 8 (interface between the base material 1 and the primer layer 2), and peeling 9 occurs (FIG. 5 (III)).

  Therefore, the covering member of the present invention includes a resin base material 1 and a primer layer 2 made of a resin primer formed on the surface of the resin base material 1 as shown in FIG. The hard coat layer 3 formed on the primer layer 2 and containing the flexibility-imparting agent 31, and the primer layer 2 and / or the hard coat layer 3 includes the ultraviolet absorbers 20 and 30. .

  The covering member of the present invention has a hard coat layer containing a flexibility imparting agent. Since the flexibility is imparted to the hard coat layer by the flexibility imparting agent, cracking and peeling of the coating caused by the hardness difference between the hard coat layer, the primer layer, and the resin substrate are reduced, and It becomes a covering member excellent in crack property and adhesion. In addition, because the limit elongation amount of the hard coat layer is increased by the flexibility imparting agent, the primer layer repeatedly expands and contracts due to temperature changes, etc., and cracks occur even if the hard coat layer is cured due to cross-linking over time. Difficult and weather resistant.

As the flexibility imparting agent, various commonly used flexibility imparting agents may be used. For example, the flexibility imparting agent can be used if it has an average particle size that is small enough to maintain the transparency of the hard coat layer, and is preferably 1000 nmφ or less, more preferably 500 nmφ or less. Further, the average particle diameter of the flexibility imparting agent is preferably as small as possible, but may be 0.1 nmφ or more. If it is in said range, flexibility can be provided to a hard-coat layer, without impairing the abrasion resistance of a hard-coat layer, and the limit elongation amount of a hard-coat layer can be increased effectively. Specifically, R1 _a SiX1 _(4-a) (wherein R1 represents an organic group having 1 to 18 carbon atoms, X1 represents a hydrolyzable group, and a is an integer of 0 to 2). Various kinds of polysiloxane resins, acrylic resins, polyester resins, polyurethane resins, etc. obtained by hydrolyzing and condensing at least one hydrolyzable silicon compound (except when only a = 0 and only when a = 2) Resin; Silicon rubber solution or fine particles obtained by partially or fully cross-linking diorganosilicone containing hydrolyzable silyl group or polymerizable group-containing organic group, or various rubber solutions or fine particles such as polyurethane rubber and acrylonitrile rubber Etc. In particular, a silicone resin is suitable.

  And, if the flexibility imparting agent is 3 to 60 wt%, it is possible to reduce the occurrence of cracking and peeling of the film while maintaining the scratch resistance, and in addition to adhesion and crack resistance, the scratch resistance is also excellent. It becomes a covering member. In addition, the ratio of the said flexibility imparting agent is a ratio when the formed hard-coat layer is 100 wt%, More preferably, it is 5-60 wt% and 10-60 wt%.

The hard coat layer is not particularly limited as long as it is formed using a commonly used hard coat coating composition, but polysiloxane (—Si—O—) _n or polysilazane (—Si—N—) _n. A film containing silicon oxide formed by curing a coating composition made of a silicon-containing polymer represented by Specifically, R1 _a SiX1 _(4-a) (wherein R1 represents an organic group having 1 to 18 carbon atoms, X1 represents a hydrolyzable group, and a is an integer of 0 to 2). At least one hydrolyzable silicon compound (except when only a = 0 and only when a = 2) is hydrolyzed with 1 mol or more of water per 1 mol of hydrolyzable group (X1). Condensed polysiloxanes, or mixtures of these polysiloxanes with fine metal oxide particles such as silica sol and titanium oxide, and R1 _a SiX2 _(4-a) (wherein R1 and a are the same as above, X2 Or a polysilazane obtained by reacting at least one hydrolyzable halogenosilicon compound (except for the case of only a = 0 and the case of only a = 2) with ammonia, or these polysilazanes When And the like a mixture of a metal oxide fine particles such as Rikazoru or titanium oxide.

  Among them, as disclosed in JP-A-2001-348528 (Patent Document 2), β of a mixture containing an organosilicon compound having a hydrolyzable group-containing silyl group, titanium tetraalkoxide and other metal alkoxides. -If it is a hard-coat layer using the coating agent composition containing the reaction product and / or hydrolysis-condensation product with diketone, it will become a coating | coated member excellent in abrasion resistance and a weather resistance further.

The hard coat layer may contain an ultraviolet absorber. The hard coat layer containing the ultraviolet absorber can suppress the photodegradation of the resin substrate, and as a result, the weather resistance adhesion between the resin substrate and the primer layer is improved. As the ultraviolet absorber, for example, various particulate ultraviolet absorbers can be used, and particularly preferably, titanium oxide (TiO ₂ ), cerium oxide (CeO ₂ ), zinc oxide (ZnO), zirconium oxide (ZrO ₂ ). ), Tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ , ITO: Indium Tin Oxide) and other inorganic oxide fine particles.

  Further, as disclosed in JP-A No. 2001-348528 (Patent Document 2), it is a metal compound composed of a reaction product and / or hydrolysis condensate of a mixture containing titanium tetraalkoxide with a β-diketone. May be. The ultraviolet absorber is preferably one having a low sublimation property and less loss of the ultraviolet absorber due to light or water over time. It is possible to reduce the ultraviolet deterioration on the surface of the resin base material and maintain the adhesiveness between the resin base material and the coating (primer layer) for a long period of time, so that the coated member is excellent in weather resistance adhesiveness.

  At this time, when the hard coat layer is 100 wt%, it is preferable to contain 0.1 to 20 wt% of the ultraviolet absorber. If the ratio of the ultraviolet absorber is within the above range, the characteristic of suppressing the photodegradation of the resin substrate can be effectively exhibited without impairing the scratch resistance of the hard coat layer. More preferable ratios of the ultraviolet absorber are 0.3 to 20 wt% and 0.5 to 10 wt%. If the ultraviolet absorber is in the form of fine particles, the average particle size is preferably about 0.1 to 500 nmφ, more preferably 1 to 100 nmφ and 1 to 50 nmφ.

  Furthermore, if a hard coat layer is formed using an organopolysiloxane composition to which silica fine particles or colloidal silica is added, a coated member having high scratch resistance can be obtained.

  The thickness of the hard coat layer depends on the kind of the hard coat layer and the kind of the ultraviolet absorber, but the film thickness is preferably 3 to 5 μm. When the thickness of the hard coat layer is in the above range, cracks and peeling are effectively reduced, and the hard coat layer is excellent in scratch resistance. Further preferable thicknesses of the hard coat layer are 3 to 4.8 μm and 3 to 4.5 μm.

  And the coating | coated member of this invention has a primer layer which consists of a resin primer. The primer layer improves the adhesion between the resin substrate and the hard coat layer. Since the primer layer consists of resin primers, additional properties such as hardness, wear resistance, and light properties can be easily achieved by mixing resin primers with different properties or mixing fine particles such as metals and oxides. Can be added. The resin primer for forming the primer layer is not particularly limited as long as it is a general resin primer, but preferred resin primers include epoxy resin, urethane resin, polyester resin, melamine resin, phenol resin, polyamide, ketone resin, vinyl resin. And various acrylic resins such as a thermosetting acrylic resin, a moisture curable acrylic resin, a thermoplastic acrylic resin, and an acrylic resin modified with silane or siloxane. Moreover, these can also be used individually or in combination of 2 or more types. Among these, an acrylic primer mainly containing various acrylic resins is particularly preferable.

  Specifically, a thermosetting and / or moisture curable (meth) acrylic resin which is a copolymer containing a reactive group-containing (meth) acrylic acid derivative as a monomer component or a non-reactive (meth) ) Thermoplastic (meth) acrylic resin comprising acrylic acid esters.

  Examples of reactive group-containing (meth) acrylic acid derivatives include 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 1- [3- (meth) acryloxypropyl] pentamethoxydisilane, 1- [3- (meth) acryloxypropyl] -1-methyl-tetramethoxydisilane, 3- (meth) acryloxypropylsilane and tetramethoxysilane Alkoxysilyl group-containing (meth) acrylic acid derivatives such as co-hydrolyzed condensate with 1, co-hydrolyzed condensate of 3- (meth) acryloxypropylsilane and methyltrimethoxysilane; 2-hydroxyethyl (meth) acrylate , 3-hydroxypropyl (meth) acrylate, 4-hydro Cibutyl (meth) acrylate, glycerin mono (meth) acrylate, pentaerythritol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate (the number of ethylene glycol units is, for example, 2 to 20), polypropylene glycol mono (meth) acrylate (propylene The number of glycol units is, for example, mono (meth) acrylic acid esters of polyhydric alcohols such as 2 to 20); (meth) acrylic acids such as (meth) acrylic acid; 2-aminoethyl (meth) acrylate, (meth) ) Amino group-containing (meth) acrylic acid esters such as 2- (N-methylamino) ethyl acrylate; and epoxy group-containing (meth) acrylic acid esters such as glycidyl (meth) acrylate.

  Non-reactive (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylic acid n. -Butyl, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, (meth) acryl N-decyl acid, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-methylcyclohexyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, (meth ) Isobornyl acrylate, dicyclopentanyl (meth) acrylate, dicyclo (meth) acrylate (Meth) acrylic acid esters of monohydric alcohols such as tertenyloxyethyl and benzyl (meth) acrylate; (meth) acrylic acid monomers having a cyclic hindered amine structure; 2- (2′-hydroxy-5 ′) -(Meth) acryloxyphenyl) -2H-benzotriazole, 2- [2'-hydroxy-5 '-(2- (meth) acryloxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy -3′-methyl-5 ′-(8- (meth) acryloxyoctyl) phenyl] -2H-benzotriazole, 2-hydroxy-4- (2- (meth) acryloxyethoxy) benzophenone, 2-hydroxy-4 -(4- (meth) acryloxybutoxy) benzophenone, 2,2'-dihydroxy-4- (2- (meth) acryloxyate Xyl) benzophenone, 2,4-dihydroxy-4 ′-(2- (meth) acryloxyethoxy) benzophenone, 2,2 ′, 4-trihydroxy-4 ′-(2- (meth) acryloxyethoxy) benzophenone, Contains UV-absorbing groups such as 2-hydroxy-4- (3- (meth) acryloxy-2-hydroxypropoxy) benzophenone and 2-hydroxy-4- (3- (meth) acryloxy-1-hydroxypropoxy) benzophenone (meta ) Acrylic acid derivatives can be mentioned.

  The acrylic primer contains a thermosetting acrylic resin and a thermoplastic acrylic resin, and the weight ratio of the thermosetting acrylic resin to the thermoplastic acrylic resin is preferably 95: 5 to 30:70. By using the thermoplastic acrylic resin in the above weight ratio range, the linear expansion coefficient of the primer layer can be reduced while maintaining the effect of the primer layer as a primer. As a result, since the stress due to the expansion / contraction of the primer layer that occurs due to the temperature change with time decreases, the cracks generated in the coating can be reduced. More preferably, the weight ratio of the thermosetting acrylic resin to the thermoplastic acrylic resin is 90:10 to 35:65, and further 80:20 to 40:60.

  The acrylic primer preferably has a weight average molecular weight of 5,000 to 800,000 of the thermoplastic acrylic resin. The glass transition temperature Tg of the thermoplastic resin is expressed by Tg = Tg∞−K ′ / M (Tg∞ is the glass transition temperature of a polymer having an infinite molecular weight, K ′ is a constant, and M is a molecular weight). As T is larger, Tg tends to be higher. Therefore, by setting the weight average molecular weight of the thermoplastic acrylic resin within the above range, the movement of the primer layer (polymer thermal movement) at a high temperature can be reduced. As a result, since the stress caused by the flow at high temperature is reduced, cracks generated in the coating can be reduced. Further, the weight average molecular weight of the thermoplastic acrylic resin is preferably 10,000 to 700,000, and more preferably 15,000 to 600,000.

  The primer layer may contain an ultraviolet absorber. The primer layer containing the ultraviolet absorber can suppress the photodegradation of the resin substrate, and as a result, the weather resistance adhesion between the resin substrate and the primer layer is improved. As the ultraviolet absorber, for example, various commonly used inorganic and organic ultraviolet absorbers can be used, and particularly preferred is an immobilized ultraviolet absorber fixed to a resin primer by a chemical bond. . Since the immobilized ultraviolet absorber has low sublimability, it is possible to suppress the disappearance of the ultraviolet absorber over time due to light or water. As a result, the ultraviolet deterioration of the surface of the resin substrate can be reduced, and the adhesion between the resin substrate and the primer layer can be maintained. In particular, as disclosed in JP-A-2001-214122 (Patent Document 1), a UV-absorbing vinyl monomer and a vinyl monomer containing an alkoxysilyl group can be copolymerized. If a primer layer using an alkoxy group-containing organic copolymer that is a copolymer of the above monomer as an undercoat composition is used, a coated member having higher adhesion and excellent weather resistance can be obtained.

  The amount of the ultraviolet absorber immobilized in the primer layer is preferably 3 to 25 wt% with respect to 100 wt% of the primer layer. If it is less than this, the ultraviolet absorbing performance is not sufficient, the weather resistance adhesion is lowered, and the covering member is likely to be peeled off. If it is more than this, the adhesion between the primer layer and the hard coat layer will be lowered, making it difficult to adhere from the beginning. More preferable amounts of the ultraviolet absorber are 5 to 20 wt% and 8 to 20 wt%.

  The thickness of the primer layer depends on the type of resin primer used as the primer and the type of ultraviolet absorber, but when the primer layer contains an ultraviolet absorber, the thickness is preferably 8 μm or more. If the thickness of a primer layer is 8 micrometers or more, since the upper limit of the ultraviolet absorber which can be added to a primer layer increases, the photodegradation of the resin-made base materials can be reduced further effectively. As a result, the weather resistance adhesion between the resin substrate and the primer layer is further improved. Further, the thickness of the primer layer is more preferably 8 to 16 μm. If the thickness of the primer layer is within this range, good weather resistance can be imparted to the covering member while sufficiently bonding the resin base material and the hard coat layer. In general, it is known that when the film thickness is increased, cracking and peeling are likely to occur. However, in the covering member of the present invention, a primer is formed by a hard coat layer containing a flexibility-imparting agent. Even if the thickness of the layer is 8 μm or more, peeling and peeling are reduced. A more preferable primer layer thickness is 8.5 to 15.5 μm.

  The primer layer and hard coat layer are formed by applying a coating composition prepared with the desired ingredients (adjusting the viscosity with a solvent if necessary) on the surface of the resin substrate or primer layer and then curing it. It is desirable to do. As the coating method, for example, a coating method, a spray coating method, a flow coating method, a spin coating method, a dip coating method and the like are possible. Moreover, the coating composition may be cured by appropriately selecting a temperature and time suitable for the composition.

  The resin substrate is not particularly limited as long as it is a substrate made of a resin material having characteristics such as impact resistance and transparency according to the application of the covering member. For example, if it is used as an organic glass for a window glass of an automobile, a transparent resin substrate such as polycarbonate, polymethyl methacrylate, or polystyrene is preferable.

  The transparent resin substrate is preferably a sunroof substrate made of polycarbonate. Polycarbonate has sufficient transparency and impact resistance. Therefore, the covering member of the present invention using polycarbonate as a transparent resin substrate can be suitably used as a sunroof that can be freely opened and closed in an opening formed in a window glass for automobiles, particularly a vehicle roof panel. Specifically, as shown in FIG. 1, the frame 4 and the covering member 1 ′ of the present invention, the periphery of which is supported by the frame 4, the periphery of the covering member 1 ′ and the frame 4. In general, a loop-shaped weather strip 5 made of a flexible material such as rubber is attached. The weather strip 5 ensures airtightness in the vehicle. The covering member 1 ′ has at least a primer layer and a hard coat layer on the vehicle outer surface (see FIG. 2).

  Note that the covering member of the present invention is not limited to the above-described embodiment, and in order to add other functions, the drying member, the light stabilizer, the antistatic agent, etc. These materials may be mixed. In particular, when a water repellent is added to the hard coat layer, peeling between the substrate and the primer layer can be effectively prevented. Moreover, in addition to a primer layer and a hard-coat layer, you may have a film of 3 or more layers by forming another layer.

  Below, the Example of the coating | coated member of this invention is described using FIGS. 1-3.

[Preparation of primer layer coating composition P]
[Primer P1]
A flask equipped with a stirrer, a condenser and a thermometer was charged with 152.3 g of diacetone alcohol as a solvent and heated to 80 ° C. under a nitrogen stream. 240 g of a monomer mixed solution (90 g of γ-methacryloxypropyltrimethoxysilane, 337.5 g of methyl methacrylate, 22.5 g of glycidyl methacrylate, 350 g of diacetone alcohol) prepared in advance, and 54 g of a solution prepared by dissolving 2.3 g of 2,2′-azobis (2-methylbutyronitrile) as a polymerization initiator in 177.7 g of diacetone alcohol was sequentially added. After reacting at 80 ° C. for 30 minutes, the remaining monomer mixed solution and the remaining polymerization initiator solution were simultaneously added dropwise at 80 to 90 ° C. over 1.5 hours. Furthermore, it stirred at 80-90 degreeC for 5 hours, and obtained the thermosetting acrylic resin coating composition.

  The obtained thermosetting acrylic resin coating composition and a polymethylmethacrylate resin (Mitsubishi Rayon Co., Ltd. Dianar BR-88 (weight average molecular weight 480,000) propylene glycol monomethyl ether solution in a solid content mass ratio of 8: 2, when the total solid content of the thermosetting acrylic resin coating composition and the polymethyl methacrylate resin is 100 parts by mass, 12 parts by mass of 2,4-dihydroxybenzophenone as an organic ultraviolet absorber, and silane A coupling agent (KBP-43 manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 10 parts by mass, mixed and adjusted with propylene glycol monomethyl ether so that the non-volatile content (JIS K6833) was 12%. Obtained.

[Primer P2]
A flask equipped with a stirrer, a condenser and a thermometer was charged with 152.3 g of diacetone alcohol as a solvent and heated to 80 ° C. under a nitrogen stream. A monomer mixed solution prepared in advance (2- [2′-hydroxy-5 ′-(2-methacryloxyethyl) phenyl] -2H which is a UV-absorbing group-containing (meth) acrylic acid derivative) -240 g of 36 g of benzotriazole (RUVA-93 manufactured by Otsuka Chemical Co., Ltd.), 90 g of γ-methacryloxypropyltrimethoxysilane, 301.5 g of methyl methacrylate, 22.5 g of glycidyl methacrylate, 350 g of diacetone alcohol, and prepared in advance 54 g of a solution prepared by dissolving 2.3 g of 2,2′-azobis (2-methylbutyronitrile) as a polymerization initiator in 177.7 g of diacetone alcohol was sequentially added. After reacting at 80 ° C. for 30 minutes, the remaining monomer mixed solution and the remaining polymerization initiator solution were simultaneously added dropwise at 80 to 90 ° C. over 1.5 hours. Furthermore, it stirred at 80-90 degreeC for 5 hours, and obtained the thermosetting acrylic resin coating composition by which the ultraviolet absorber was fix | immobilized.

  The obtained thermosetting acrylic resin coating composition and a polymethylmethacrylate resin (Mitsubishi Rayon Co., Ltd. Dianar BR-88 (weight average molecular weight 480,000) propylene glycol monomethyl ether solution in a solid content mass ratio of 6: When the solid content of the thermosetting acrylic resin coating composition and the polymethyl methacrylate resin is 100 parts by mass when mixed with 4, 10 parts by mass of a silane coupling agent (KBP-43 manufactured by Shin-Etsu Chemical Co., Ltd.) After adding and mixing, the mixture was adjusted with propylene glycol monomethyl ether so that the non-volatile content (JIS K6833) was 12% to obtain primer P2.

[Primer P3]
Primer P3 was obtained in the same manner as Primer P2, except that polymethylmethacrylate resin was made by Mitsubishi Rayon Co., Ltd. Dianal BR-80 (weight average molecular weight 95,000).

[Preparation of coating composition H for hard coat layer]
[Hard coat H1]
A flask equipped with a stirrer, a condenser and a thermometer was charged with 336 g of methyltriethoxysilane and 94 g of isobutanol and maintained at 5 ° C. or lower while stirring under ice cooling. After adding 283 g (Nissan Chemical Co., Ltd. Snowtex O (average particle size 15-20 nm), SiO ₂ 20% -containing product) and stirring for 3 hours under ice-cooling and further for 12 hours at 20-25 ° C., 27 g of acetone alcohol and 50 g of propylene glycol monomethyl ether were added. Subsequently, 3 g of 10% sodium propionate aqueous solution and 0.2 g of a polyether-modified silicone (KP-341 manufactured by Shin-Etsu Chemical Co., Ltd.) as a leveling agent were added, and the pH was adjusted to 6 to 7 with acetic acid. And it adjusted with isobutanol so that a non volatile matter (JIS K6833) might be 20%, and it age | cure | ripened at normal temperature for 5 days, and obtained the colloidal silica containing organopolysiloxane composition.

  To the obtained colloidal silica-containing organopolysiloxane composition, 2,4-dihydroxybenzophenone as an organic ultraviolet absorber was added and mixed so as to be 3 wt% of the hard coat layer after curing to obtain a hard coat H1. .

[Hard coat H2]
A flask equipped with a stirrer, a condenser and a thermometer was charged with 170.6 g (0.6 mol) of titanium tetraisopropoxide and 38.4 g (0.1 mol) of zirconium tetra-n-butoxide and stirred at room temperature. Then, 70 g (0.7 mol) of acetylacetone was added dropwise over 30 minutes using a dropping funnel. At this time, the internal temperature rose to 63 ° C. After stirring and aging for 1 hour at room temperature, 44.6 g of 3% aqueous hydrochloric acid (water 2.38 mol) was added dropwise over 20 minutes. Then, the reaction was carried out at 70 to 80 ° C. for 10 hours to obtain a light yellowish brown transparent metal compound solution having a pH of 2.79. This metal compound solution absorbs light having a wavelength of 350 nm or less according to an absorbance analysis using a solution diluted with ethanol so that the solid content concentration is 0.05 g / L.

  6 parts by mass of the obtained metal compound solution was added to and mixed with 100 parts by mass of the solid content of the hard coat H1 to obtain a hard coat H2.

[Hard coat H3]
100 parts by mass of 20% isobutanol solution of a silicone resin (KR-220L manufactured by Shin-Etsu Chemical Co., Ltd.) as a flexibility imparting agent is added to and mixed with 100 parts by mass of the solid content of the hard coat H2. Hard coat H3 was obtained.

[Preparation of Samples A to D]
A polycarbonate substrate (ML300T manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was prepared as a substrate for resin base material sunroof.

  After applying any of the primer layer coating compositions P1 to P3 to a desired thickness on the sunroof substrate 1 having a cleaned surface by a dip coating method, drying and baking (125 ° C. for 45 minutes) The primer layer 2 was formed by curing. Next, after applying any of the coating compositions H1 to H3 for the hard coat layer by a flow coat method so as to have a desired film thickness, drying and baking (at 130 ° C. for 60 minutes) to cure the hard coat layer Layer 3 was formed. Table 1 shows the type of coating composition used for each sample and the film thickness of each layer. Table 2 shows main compositions of the primer layer and the hard coat layer of each sample.

  2 is a cross-sectional view schematically showing the sample C and the sample D, and corresponds to a cross section in the X-X ′ direction of FIG. 1 when assembled as a sunroof. The covering member 1 ′ of the sample C and the sample D is formed on the sunroof substrate 1, the primer layer 2 formed on the surface of the sunroof substrate 1 and containing the immobilized ultraviolet absorber 20, and formed on the primer layer 2 to absorb ultraviolet rays. Hard coat layer 3 containing agent 30 and silicone resin 31.

<Evaluation>
A weather resistance test was performed on Sample A to Sample D. The weather resistance test is a time (SUV cycle number) until a xenon lamp type accelerated weather resistance test (JIS K1415) using a xenon weather meter (hereinafter referred to as “XENON”) is performed and cracking or peeling can be visually confirmed. ) Was measured. The results of the weather resistance test are shown in FIG. Note that “%” and “peel” in FIG. 3 indicate which of the samples was confirmed to be cracked or peeled.

  According to the weather resistance test, Sample C and Sample D having a hard coat layer containing a silicone resin (flexibility imparting agent) have a time until the coating is cracked or peeled off more than twice that of Sample A. It is a covering member that is superior in weather resistance adhesion and weather crack resistance than conventional. Sample C and Sample D were more excellent in weather resistance adhesion and weather cracking than Sample B because the content of the immobilized ultraviolet absorber contained in the primer layer was increased by increasing the thickness of the primer layer. It becomes a covering member.

  Further, Sample C and Sample D showing a weather resistance performance of 3000 hours or more with XENON are suitable for, for example, a sunroof for automobiles and the like because of having excellent weather adhesion and weather cracking resistance.

It is a perspective view which shows typically the case where the coating | coated member of this invention is used for the sunroof for motor vehicles. It is sectional drawing in X-X 'of the sunroof for motor vehicles of FIG. 1, Comprising: It is explanatory drawing which shows a coating | coated member. It is a graph which shows time until a crack or peeling can be visually confirmed in a film in a xenon lamp type accelerated weathering test about samples AD. It is sectional drawing of the conventional coating | coated member, Comprising: It is a schematic diagram explaining the mechanism which a crack produces in a film. It is sectional drawing of the conventional coating | coated member, Comprising: It is a schematic diagram explaining the mechanism in which a film peels.

Explanation of symbols

1: Resin base material (substrate for sunroof)
1 ': Cover member (used for sunroof) 2: Primer layer 20: (Immobilized) UV absorber 3: Hard coat layer 30: (Inorganic) UV absorber 31: Flexibility imparting agent

Claims (10)

A resin base material, a primer layer formed on the surface of the resin base material, and a hard coat layer formed on the primer layer,
The primer layer includes a thermosetting acrylic resin and a thermoplastic acrylic resin, and an acrylic primer (provided that the weight ratio of the thermosetting acrylic resin to the thermoplastic acrylic resin is 95: 5 to 30:70) , Except for acrylic primers including PC-7A manufactured by Shin-Etsu Chemical Co., Ltd. and PUVA-30M manufactured by Otsuka Chemical Co., Ltd.)
The hard coat layer contains 3 to 60 wt% of a flexibility imparting agent when the hard coat layer is 100 wt% ,
Prior Symbol primer layer and / or the hard coat layer, the covering member, which comprises a UV absorber. The covering member according to claim 1, wherein the hard coat layer includes a silicone resin as the flexibility imparting agent .   The covering member according to claim 1, wherein the primer layer contains an ultraviolet absorber and has a thickness of 8 μm or more.   The covering member according to claim 1, wherein the acrylic primer has a weight average molecular weight of 5,000 to 800,000 of the thermoplastic acrylic resin.   The covering member according to claim 1, wherein the ultraviolet absorber included in the primer layer is an immobilized ultraviolet absorber fixed to the resin primer by a chemical bond.   The covering member according to claim 1, wherein the hard coat layer is a film containing silicon oxide.   The covering member according to claim 1, wherein the ultraviolet absorber included in the hard coat layer is an inorganic ultraviolet absorber.   The covering member according to claim 1, wherein the hard coat layer has a thickness of 3 to 5 μm.   The covering member according to claim 1, wherein the resin base material is a transparent resin substrate having transparency.   The covering member according to claim 9, wherein the transparent resin substrate is a sunroof substrate made of polycarbonate.

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